There are plating devices that plate substrates held on a substrate holder. With such a plating device, substrates may be displaced from their proper position when they are mounted on and/or dismounted from the substrate holder. Such displacement of a substrate could be caused, for example if the substrate holder, the table on which the substrate holder is mounted, or the substrate is warped or if the substrate holder is tilted by droplets present on a surface of the substrate or dust on the table. The displacement in position creates the possibility that a plating process may not be properly performed on a workpiece to be plated, that is, the substrate.
There have been proposed techniques for detecting the position of a substrate when it is mounted on the substrate holder and correcting the position of the substrate if it is out of proper position (for example, Japanese Patent No. 5750327 (Patent Literature 1)). According to the technique described in Japanese Patent No. 5750327 (Patent Literature 1), a securing/retaining member 15 of a substrate holder 110 is provided with a notch 17 at a position corresponding to an edge of a substrate 500, and a laser sensor 1140 is disposed so that when the substrate is placed in proper position, a surface of the notch can be irradiated without being blocked by the substrate 500. When the substrate 500 is placed on the securing/retaining member 15, the laser sensor 1140 measures distance. If the distance measured is a distance A to the notch 17, it is determined that that the substrate 500 is not out of position. On the other hand, if the distance measured is a distance W1 (<A), the substrate 500 is determined to be out of position. This technique requires modifying the design of many substrate holders to be used, providing the substrate holders with the notch 17 for position detection. If the substrate holder itself is thin, there may be difficulty in forming such a notch to ensure sufficient accuracy in detection.
Further, in general, various semiconductor manufacturing devices may in future be required to process with relatively high accuracy a variety of substrates that have not existed so far, for example, more intricately patterned substrates and substrates of more varying semiconductor material than conventional ones. These substrate manufacturing devices are expected to be more accurate than the existing ones, for example in transferring substrates onto the processing table and positioning them.